This invention relates generally to vapor phase processes for doping a silicon layer, and more particularly, to controlled layer-by-layer vapor phase deposition of phosphorous, boron, arsenic, antimony compounds for controlled doping of silicon.
Miniaturization of silicon-based devices requires careful doping of the silicon contacts and/or channel regions. Standard doping approaches include high-energy ion implantation, which tends to produce problems such as amorphization of the silicon, and the like, which can significantly degrade device performance. Another approach that has been considered is doping through self-assembly of phosphorous or boron containing organic compounds followed by capping with an oxide layer and annealing step at high temperature to activate the dopants. Although the extent of doping can be controlled in this approach, the presence of carbonaceous species results in diffusion of carbon and the formation of unwanted carbides in the silicon.
Accordingly, there remains a need for improved doping processes for silicon.